This invention concerns pressure sensitive adhesive laminates (comprising typically of a facestock, adhesive and release coated liner) that are used to primarily make signs. The sign may be used on the side of vehicles for the purposes of advertisement, decoration, and/or information. The desirable functional features of such laminates, include the ability to readily hand-peel the adhesive containing film off from the release liner and apply on to a variety of substrates during hot or cold seasons; conform well over rivets and corrugation (to look as though the graphics containing laminate signs were painted); allow for the ability to reposition the laminate by minimizing initial adhesion to substrate; minimize or eliminate trapping of air bubbles during application to substrates; offer excellent compatibility with various printing techniques as well as good reception to various type of printing inks; tolerate a wide variation in outdoor weather conditions such as rain, solar irradiation, winter as well as summer temperatures; remove cleanly when desired from the side of these vehicles without leaving adhesive residue or film breaking due to becoming brittle and offer sufficient adhesion to various metal and painted and plastic substrates over a wide range of temperatures spanning from summer to winter months. Obtaining all the desirable product attributes successfully within a laminate is, therefore, quite a challenge that requires the skillful combination of facestock, adhesive and release liner with optimum requisite properties.
U.S. Pat. No. 3,728,148 deals with a PSA for electrical tapes and teaches the use of an alkyl acrylate ester with 10-30% of a N-vinyl lactam and a modifying comonomer.
U.S. Pat. No. 4,364,972 deals with a PSA containing an alkyl acrylate ester and 15-50 parts by weight of N-vinyl pyrrolidone. The adhesive has high adhesion and cohesion and adheres strongly to paints, rubber or plastic foam. The application contemplated is to adhere plastic molding strips to autos.
U.S. Pat. No. 4,370,380 deals with a blend of two polymers. First polymer is a water soluble polymer of a vinyl lactam with 1-80 mole % of a comonomer. Second polymer is a tacky water insoluble copolymer of an acrylate ester with 1-12% by weight of an acidic comonomer. The resulting pressure-sensitive adhesive has moisture permeability and is used for skin adhesion.
U.S. Pat. No. 4,510,197 deals with a water vapor permeable PSA comprising from about 79-89% of n-butyl acrylate, from about 10-20% of a hydrophilic n-vinyl lactam and from about 1-5% of an acid containing comonomer.
U.S. Pat. No. 4,818,610 deals with a tape having a plurality of layers which cannot be delaminated due to migration polymer chains of the contiguous layers. A PSA of an alkyl acrylate with a minor proportion of polar copolymerizable monomers selected from n-vinyl pyrrolidinone and acrylic acid is disclosed.
U.S. Pat. No. 4,968,562 deals with a hollow, inherently tacky removable microsphere PSA containing nitrogen and acid free.
U.S. Pat. No. 4,988,742 deals with a PSA terpolymer comprising a) from 60-95 parts of a photopolymerized polymer of monomers containing i) 60-96 parts alkyl acrylate, ii) 2 to 15 parts of a strongly polar copolymerizable monomer, iii) 2 to 25 parts of a strongly polar and moderately polar monomer, b) 40 to 5 parts of hydrogenated rosin ester tackifier and c) 0.01 to 1 parts of a photoinitiator. These tackified polymers are alleged to have lower Tg than polymers of the same composition without tackifier. These polymers are alleged to have significantly higher shear and adhesion to lower energy substrates.
EP 303430 deals with a PSA comprising 50-95 parts of UV polymerized polymer of I) acrylate and ii) 2-15 parts of a strongly polar comonomer and iii) 0 5-30 parts of moderately polar monomer such as N— vinyl pyrrolidinone, N-vinyl caprolactam, further comprising 0.01-1 wt. % crosslinker and b) 5-50 parts of t-butyl styrene tackifier.
EP 324242 deals with a foam like PSA tape where the PSA comprises of a) polymer of 70-100 parts of acrylate and b) 30-0 parts of a moderately polar comonomer selected from NVP, N-vinyl caprolactam and c) 0.01 to 1 part of hexanediol diacrylate, amino formaldehyde or trihalotriazine crosslinking agent.
EP 342811 deals with a PSA comprising 60-88 parts of an alkyl acrylate, 2-30 parts of a polar nitrogen containing vinyl monomer, and 0-12 parts of a vinyl carboxylic acid, said copolymer being intimately blended with 2-25% of plasticizer. Excellent shear adhesion retention after prolonged contact with plasticized vinyl substrate is claimed.